Suppose that Office 2016 Pro Plus (MS ActionPack, MSDN subscription etc.) is installed on your PC but you still need to add some language support. In my case, I need to add the Russian proof tools to the English Office that includes already the French language support but doesn't contain any Cyrillic spell checking.

Here is the check list of Windows 10 services that may be deactivated to free some memory and other resources.

'Connected User Experiences and Telemetry' service (previously 'Diagnostics Tracking Service' in Windows 7/8/2012). Unfortunately, it is not sufficient, you should also go to Task Sheduler and disable all tasks in the folder \Microsoft\Windows\Application Experience. Also check that they are still disabled after any Windows update